Live Streaming

Live streaming support in Radiant Media Player

Live streaming has become increasingly popular over the past few years in the streaming media industry. Radiant Media Player supports live video & audio streaming with the following streaming protocols:

• HLS including LL-HLS (low-latency HLS)
• MPEG-DASH including LL-DASH (low-latency DASH)

Our general recommendations and advanced player settings for HLS streaming and MPEG-DASH streaming also apply to live streaming.

Radiant Media Player sports a variety of optimisations for live streaming and a dedicated live UI. Upon startup, the player will detect if a stream is a live stream, and if so, will automatically trigger live optimisations.

You can also insert video advertisement (including VMAP or our ad-scheduler), use DRM, stream 360° video content and query our player API with live streaming to our player. A dedicated Live API is available.

Documentation for using Radiant Media Player with DVR streams can be found here.

Latency considerations

Live latency is a real-world source of worry for live streamers. The below graphic shows what to expect when it comes to latency for HLS or MPEG-DASH live streaming. If latency is a priority for you, you should consider using low-latency HLS or low-latency MPEG-DASH. Radiant Media Player supports specification-compliant low-latency live streaming with HLS and MPEG-DASH out of the box. Refer to the documentation of your streaming server to enable server-side live low-latency streaming with HLS or MPEG-DASH, the player will automatically enter low-latency mode when it detects a low-latency stream.

Live HLS streaming player code example

Using HLS you can reach all supported devices by Radiant Media Player for live streaming.

<!-- Include Radiant Media Player - here we use the optimised build for hls.js -->
<script src="https://cdn.radiantmediatechs.com/rmp/9.16.6/js/rmp-hlsjs.min.js"></script>
<!-- Player container element -->
<div id="rmp"></div>
<!-- Set up player configuration options -->
<script>
  // Live HLS streaming source
  const src = {
    hls: 'https://your-live-hls-url.m3u8'
  };
  // Your player settings
  const settings = {
    licenseKey: 'your-license-key',
    src: src,
    width: 640,
    height: 360,
    contentMetadata: {
      poster: [
        'https://your-poster-url.jpg'
      ]
    }
  };
  const rmp = new RadiantMP('rmp');
  rmp.init(settings);
</script>

Low latency live HLS streaming (LL-HLS)

We support Low-Latency HLS (LL-HLS) according to Apple HLS specification. This includes support for the new Media Playlist Tags:

• EXT-X-SERVER-CONTROL
• EXT-X-PART-INF
• EXT-X-PART
• EXT-X-PRELOAD-HINT
• EXT-X-RENDITION-REPORT
• EXT-X-SKIP

LL-HLS streams are automatically detected by the player and when this happens playback is automatically optimised for low-latency live streaming.

Here are our recommendations for LL-HLS to work best in our player:

• GOP size: 2 seconds
• Part size: 1 second
• Segment size: 6 seconds

Please also apply Apple recommendations on the subject:

• Low-Latency stream delivery MUST meet all requirements of the Low-Latency Server Configuration Profile in Appendix B of draft-pantos-hls-rfc8216bis-07 or later
• The Part Target Duration MUST be at least the maximum round-trip time (RTT) to the server that 95% of the clients are expected to see (P95 RTT)
• The Part Target Duration SHOULD be at least three times the P95 RTT
• The RECOMMENDED Part Target Duration is one second
• The PART-HOLD-BACK value MUST be at least three times the Part Target Duration
• Services with Playlist windows longer than two minutes SHOULD offer Playlist Delta Updates
• Services that offer Playlist Delta Updates and use EXT-X-DATERANGE tags SHOULD also use CAN-SKIP-DATERANGES=YES

Live MPEG-DASH streaming player code example

iOS Safari before iOS 17 requires HLS to stream live content so including an HLS fallback when using live MPEG-DASH streaming is generally recommended.

<!-- Include Radiant Media Player - here we use the optimised build for Shaka player -->
<script src="https://cdn.radiantmediatechs.com/rmp/9.16.6/js/rmp-shaka.min.js"></script>
<!-- Player container element -->
<div id="rmp"></div>
<!-- Set up player configuration options -->
<script>
  // Live DASH streaming source
  // For iOS and older devices where DASH is not supported we use a live HLS fallback
  const src = {
    dash: 'https://your-live-dash-url.mpd',
    hls: 'https://your-live-hls-url.m3u8'
  };
  // Your player settings
  const settings = {
    licenseKey: 'your-license-key',
    src: src,
    width: 640,
    height: 360,
    // We tell the player to use DASH first over HLS when both are available
    dashFirst: true,
    contentMetadata: {
      poster: [
        'https://your-poster-url.jpg'
      ]
    }
  };
  const rmp = new RadiantMP('rmp');
  rmp.init(settings);
</script>

Low latency live MPEG-DASH streaming (LL-DASH)

We support Low-Latency DASH (LL-DASH) (CMAF-CTE - Chunked Transfer Encoding) according to DASH-IF requirements.

When streaming live, content is sent in segments that are each a few seconds long. These segments shouldn’t be shorter than 2 to 4 seconds or there could be a risk of poor performance/playback quality. With LL-DASH, if the player requests a segment which is not completed, chunks will be delivered as soon as they are available using Chunked Transfer Encoding. As media can be delivered to the client as soon as it is generated on the server side, overhead is reduced, allowing to reduce the client buffer and, as a result, latency.

LL-DASH streams are automatically detected by the player and when this happens playback is automatically optimised for low-latency live streaming.

Here are our recommendations for LL-DASH to work best in our player:

• GOP size: 2 seconds
• Chunk size: 200 milliseconds
• Segment size: 2 seconds

Live API

getLivePresentationStartTimeAsDate()

rmp.getLivePresentationStartTimeAsDate()

Returns String (ISO/IEC 8601:2004), the presentation start time date for the live stream. For HLS this is the EXT-X-PROGRAM-DATETIME value of the manifest. For DASH this is the presentationTimeOffset|availabilityStartTime value. Returns '' if not available. For an epoch time in milliseconds use: new Date(rmp.getLivePresentationStartTimeAsDate()).getTime()

getLiveCurrentTime()

rmp.getLiveCurrentTime()

Returns Number, the current time in milliseconds for the live stream. This value is relative to the current timestamp in the player (this is not an absolute value) and may only be used for relative computation. Returns -1 if player is not in live mode.

getLiveDuration()

rmp.getLiveDuration()

Returns Number, the duration in milliseconds for the live stream. This value is relative to the current timestamp in the player (this is not an absolute value) and may only be used for relative computation. Returns -1 if player is not in live mode.

syncToLiveEdge()

rmp.syncToLiveEdge()

Forces the player to resync with live edge. This can be used with live or DVR streaming (HLS or MPEG-DASH). Note that this does not apply to live HLS streaming to Apple devices as Apple uses its own HLS streaming engine that we have no control over.

Splash screen handling for timed live event

We have released a script on GitHub for splash screen handling for timed live event to be used with Radiant Media Player. We hope you find this useful for your project. This script can be used as a baseline for more advanced use-cases as well.